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Thread: Using a pneumatic cylinder to reset bolt, i.e. no bolt spring idea

  1. #1
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    Using a pneumatic cylinder to reset bolt, i.e. no bolt spring idea for increased eff.

    I just thought of this like 10 seconds ago and wanted to get it out for some ideas. I was reading about how Mags use buttloads of air since pushing the spring is so hard, and therefore crummy efficiency. What if you milled a small slit in the side of the body next to the bolt and put a little rod on the side of the bolt via a screw-in method so it could be removed to let you take out the bolt and mounted so that it would stick out and cycle when the gun fired. Now, take out the bolt spring and in its place add a pneumatic cylinder to the side of the gun connected to the rod on the bolt. That way, when you fired, the rod could be set to vent and the operating pressure that needed to be fired against the bolt spring could be greatly reduced. Then, after firing, the cylinder could actuate and push the bolt back in place. The cylinder would need a lot less air to reset the bolt than it takes for the bolt to push past the effects of the spring right now. A 3-way could be put in inside the grip frame under the sear, and it could get around the intellifeed switch by extending the trigger rod past the sear. A 3-way adds like zero force to act against, so there's still a light trigger pull, ala the ULT. A special-made foregrip regulator could be made that will split the air into two directions, one going directly to the valve and another going into the regulator for the pneumatic cylinder (note, the X-valve's air would NOT be regulated, just bypassed through the foregrip.
    What you think?

    PS- After a little thinking it might actually be possible to put the pneumatic cylinder into the rail itself. That could camouflague the entire setup, making the mag look no different and adding much improved efficiency, however it would give added complexity. However, since the body need not be sealed around the bolt area (I don't think, correct me if I'm wrong) then a simple turning of a small valve could disconnect the reg in the foregrip, putting in a bolt spring, and then an unscrewing of the little nub on the bolt and thus allow a "standard mode" incase of any failures with the reg or whatever, maybe you just want it to be standard for the time being.

    Please tell me if this kind of thing has been done before or if there are any major fallacies in my design. I was thinking that the other cocker-mag hybrids were made so that the trigger moved a 3-way which controlled a rod connected to the sear.

    What do you think? I'll try to put up some pics real fast here and show more what I'm trying to say.
    Last edited by bertmcmahan; 01-16-2004 at 10:12 PM.
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  2. #2
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    OK, after actually looking inside the frame, there really isn't room to put the 3 way where I said. Instead, it could be mounted where the switch is now, and actuated by the 3-way rod passing through the 3-way body.

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    Sorry for the UBER crappy pics, all I have is paint and Photosuite 2nd edition SE, so it's almost worthless.

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    2

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    Not a bad idea, but it may be hard to get it working.
    .

  6. #6
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    It is an interesting idea with a few flaws:
    1. The bolt spring is what makes LV X work

    2. If you remove the bolt spring you have to make the inside of the body smaller, since now the bolt has more room to wiggle sideways (it will most likely cause a powetube leak, or it could bind in the return)

  7. #7
    it wont bind or caus a leak. And level ten still works. When you reduce the spring pressure by getting a weaker spring you can lower the pressure used to operate the mag. MAking it more efficient. My LVL-10 works just fine with a lighter than normal spring.

    IN fact i am working on this very project as we speak.

    i am in the process of finding a ram that i can mount in the front.

    aut

  8. #8
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    Sweet, you gotta tell me when you're done. I think a process like this could be used to make a closed-bolt mag, which would 1- be fun and 2- driver cocker fans INSANE.

  9. Hate to burst your bubble but it probably will not work as described, since acting against the ram is 400psi and the ram only as at most 100 psi, now I suppose with a large enough ram it could be overcome, but we are talking a very large ram.

    Az

  10. #10
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    But isn't that 400 psi the pressure WITH the bolt spring? The idea with the ram was to use it to decrease operating pressure. However I do see your point, how's it gonna work with 100 psi. Hmmmmmmmm.........



    How about 2 rams? Bigger cylinder (possibly custom-made, you can get those for cheaper than name-brand cocker rams, and they can prolly handle a lot more pressure.


    Also... The ID of the ram (on smaller ones) is about the same size as the ID of the power piston, right? If you could get the gun to work at as low as 200 psi, you could have a ram with twice the ID in area of the power piston, which would not be a very large ram, and boom ther you go, the ram is powered enough. X pressure over X area=.5X pressure over 2X area.

  11. #11
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    Wait a sec, just thought of something...


    At no point would the ram push against anything but maybe SLIGHT compression of the chamber from just the power piston going in.

    Here's the series and why the ram doesn't have to work hard.
    Assume starting with the bolt cocked back with the dump chamber pressurized.

    When you fire, the sear shuts the on/off off and releases the bolt, which empties the dump chamber through the barrel, firing the gun. The bolt moves to zero resistance, save inertia, friction, and other tiny forces. We'll assume that these very small forces are not at work for the moment.
    So anyways, at this point in the cycle (which lasts an extremely short amount of time), the trigger is held back, the purge valve for the ram is held open, the on/off is off, and the bolt is foreward, not getting pushed against by anything. Upon the release of the trigger, the ram activates, pushing the bolt back to be recocked and held back by the SEAR, not the ram. The on/off is opened, and the dump chamber fills. Back to square one again. At no point in that does the ram push against any force, other than the really tiny ones.

    In defense of myself, I realize that the tiny forces involved do indeed have an effect on the cycling of a gun. I did not include them in the description above, since I was talking about much higher (in comparison) forces, like in the 100-400 range. If there's any problem with that, please LMK and I'll fix it.

  12. #12
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    Originally posted by AzrealDarkmoonZ
    Hate to burst your bubble but it probably will not work as described, since acting against the ram is 400psi and the ram only as at most 100 psi, now I suppose with a large enough ram it could be overcome, but we are talking a very large ram.

    Az
    That 400psi is only working on a very small surface area.

  13. #13
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    I know the 400 is over a very small area, however the same is true for the ram.

  14. #14
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    Just wanted to say that i had almost an exactly identical idea to this, but using a ram on the front, connected to a rod, with special "mountains" (in it tohold back the bolt. This rod would go in place of , lets say the rod used in a pump mag.
    I had a pretty detailed drawing, but threw it away since i have no way of making this.

    Just want to throw in my support, also, doesn't the paintball on recieve 65 psi from the bolt, so wouldn't that be all you had to deal with, not with the full 400?
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  15. #15
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    sounds alot like a pneumatic version of a pump mag to me...
    Proud Member Of The AO Cesspool Since 08-24-2002

  16. #16
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    Yeah, I guess you're right. It'd still be fun to make it, plus if this works then a closed-bolt mag would be feasible. For all you people saying "the dump chamber vents when the bolt is foreward" then yes I already thought of that, the bolt in my design is a 2-piece.

  17. #17
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    Congratulations. You've duplicated something I've had on the drawing board for a long time.

    I think it would work and no need for a two piece bolt. (You certainly couldn't get it to be closed bolt as-is though.)

    The problem I've had is determining how to time the thing if remaining mechanical.

    But as I alluded to in another thread, this would be the same to mags as the timmie is to spiders.

    Pull trigger, close on/off, release sear, bolt travels forward, ball leaves barrel.
    Release trigger, pressurise ram, bolt is driven back, sear is raised, on/off is opened, ram is depressurised.

    Need some sort of pressure differential valve to pressurise and depressurise the ram.

    Would be easy to do electronically though.

    Get a Morlock Board or a BASIC Stamp and have at it!

    And it would have a huge effect on the lvl10. Bolt force would be greatly increased with the spring removed.

    Now perhaps the release of pressure from the ram could be in a controlled manner after the trigger is pulled. Then you could have an adjustable level ten.

    More pressure in the ram less initial force from the lvl10. A more or less restrictive choke on the RAM pressure release would affect the performance of the rise in force from the lvl10.

  18. #18
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    The 2-piece bolt was for a closed bolt version. Still working on that one

  19. #19
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    Originally posted by bertmcmahan
    The 2-piece bolt was for a closed bolt version. Still working on that one
    Well I Knew That!

    I'd think a closed bolt version is a waste of time. I mean what's the advantage? Or are we going to revive the closed vs. open bolt debate?

    Anyways, anything you come up with will be similar to the other spool valve designs.

  20. #20
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    The closed bolt thing would just be fun to do, and it would REALLY get under the skin of all the cocker users out there! It's not supposed to be something bigger and better, just something fun to do in my spare time.

  21. #21
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    Quote Originally Posted by aut911
    it wont bind or caus a leak. And level ten still works. When you reduce the spring pressure by getting a weaker spring you can lower the pressure used to operate the mag. MAking it more efficient. My LVL-10 works just fine with a lighter than normal spring.

    IN fact i am working on this very project as we speak.

    i am in the process of finding a ram that i can mount in the front.

    aut

    Ressurrecting this thread after a few months of non-viewing...
    Aut, just wondering how you were coming on this here project? I had all but forgotten about this until recently when someone else posted it up. I'd still like to see this get done.

  22. #22
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    well, first off, the 400 psi is more like 500 psi with a level 10. at least that's what it measures at in my mag.

    second, that's not creating as much force on the bolt as you think.
    on a level 10 bolt, the small dia bolt tube is only .172" give or take a thousandth or two. this is why the lvl 10 stats out at such low force.
    if you clalculate it out, that's a surface area of .023 sq. in. now at 500 psi that's about 11.6 lbs of force pushing on the sear. the old standard bolt had WAY more pressure on the sear than this.

    if you keep using the sear, you don't need to hold the bolt back completely. you could actually just come up with close to the 11.6 lbs. a 3/8 bore ram at 100 psi(used in the extension stroke) will generate 11 lbs of force.

    now normally, the spring would be putting more force on the bolt, as the bolt came forward. but if you use a ram, and you exhaust all the pressure out of it, the bolt will fly forward fast, until you pressurize the ram again.
    it might be necessary to use a flow control valve to meter the air out of the ram and slow the bolt down a bit.

    I was thinking about using a 4-way solenoid valve to control two rams in single acting fashion. one ram would be set up just like my e-mag design. it would control the sear, the other ram would be on the bolt as discussed.
    so normally, at rest, the air would go through the 4-way N.O. port to the bolt ram, pushing back on the bolt. when the trigger was pulled it energized the 4-way, relieving the air in the bolt ram, and transfering it to the sear ram. this would fire the gun. energize time would be about 30 msec, then it would send air back to the bolt ram, to reset the bolt. a flow control could be used on the bolt ram to meter the air out. this would cause some resistance just like a bolt spring would. the difference being it would start out with alot of resistance, and end with very little, depending on the flow control setting. this would make the lvl 10 operate properly, and let the bolt gain alot of speed, where the spring would usually get stiffer. perhaps this would help reduce blowback? if you really wanted to get slick, design a bolt ram around the bolt itself, where the spring usually resides. if you could do this, ta da! you just made a matrix! well close anyway.


    a side note- rams can handle more than 100 psi. it's valves that have a problem. most solenoid valves will start to leak over 100 psi. some cocker rams use a o-ring seal that cannot handle more than 100 psi, but most rams you buy from pneumatic distributors will have u-cup seals that can handle 250 psi.

    another thing, you can buy a small 3-way valve that will fit easily into the grip frame. but I would go electronic with the project myself. more accurate and easier to trouble shoot because of it.

    now aut911- you said you are using a lighter than normal bolt spring, but do you have any idea how much pressure you are now using in the dump chamber? how much did the pressure go down from what it was before?
    personally I don't think it's as simple as just using a lighter bolt spring. otherwise I truly believe, agd would have gone with a lighter bolt spring.

    my problem is this:
    when using a lvl 10, you have to turn the pressure up right? why?
    to overcome the force of the bolt spring because the pressure in the dump chanber is not creating as much force due to the smaller surface area?
    if that's true, then why do you have to turn it up, just to get the gun to shoot, and at the same velocity it was shooting before?
    take your lvl 10 bolt out and put your standard bolt back in. notice the increase in velocity. why is this? is the lvl 10 bolt less efficient by design?

    the mag in general seems to be less efficient than other guns. why? usually higher pressure guns are a bit more efficient if only due to density at higher pressures. I think in order for a gun to be able to operate at lower pressure, it needs the air discharge path from the dump chamber(or valve) to the ball to be open and free of obstructions or objects.

    the mag in it's current design will never operate at much lower pressure than it does now. but that's just my opinion. maybe it could use the air more effeciently? I don't know.
    ~E~

  23. #23
    ok one thing about LVL-10 and using a ram to return. considering you can stick your finger in the firing chamber and fire away i doubt there would be a problem with an autococker ram pushing the bolt back due to the fact that with the regular timing of an automag, the on off valve doesnt open until bolt is in the full rearward position. My problem is turning my classic automag with a gutted hyperframe into a automocker ( my name) with the solenoid tripping the sear AND pulling the 4 way valve at the same time.

    in all likelyhood i will have to run two small 3 way valves, one attached to a tiny ram and the other to a regular autococker ram. the tiny ram trips the sear and the regular ram recocks the gun. And all this controlled by an old shocker board.

    interesting?

    aut

  24. #24
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    you don't like the single 4-way to control both idea?

    it would take up less space and use less juice.

  25. #25
    i didnt realize until after i bought the shocker board that it would be possible. the only possible problem with your design is the timing issue. I think the only way you could time your version is to use a flow restricter wich slow down the exit flow of the firing ram to allow enough time for the ram to fully return the bolt. that would possibly slow down the Max ROF for the mag but I have never actually used restricters on anything before.

    aut

  26. #26
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    Just browsing, but couldn't you use an electric solenoid to move the bolt back? Wouldn't that...
    1) Make it more gas efficient
    2) Negate the problem of overcoming a certain force (you could just get a stronger solenoid)
    3) Be really cool
    4) Get rid of the icky pneumatic valves?

    Anyhoo, don't know much about pneumatics, just thought I'd throw in my $.02


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  27. #27
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    As I said in one of my above posts, at NO point does the ram push against ANYTHING but a negligible amount of friction and the pressurization of the air chamber caused by moving the bolt back into it. Think about this series of steps:
    *Note: I am considering the ram to be in front of the bolt instead of behind, i.e., when the ram is extended the bolt is in the back position, plugging the Power tube, and also am not including anything to do with the LX.*
    1. The gun starts out ready to go, with the sear holding the bolt back, the ram extended (and it's valve in the "open" position, you'll see in a sec why this is possible), the on/off open, and the air chamber pressurized.
    2. The truigger is pulled. This shuts the on/off and moves the sear, releasing the bolt. The air in the chamber pushes against the power piston, causing the bolt to move foreward. As it moves foreward, the bolt will pull the ram along with it, with the air behind the ram being vented somewhere (grip frame or something). When the bolt is fully extended, the pressure in the air chamber and power tube vents and fires the ball.
    3. Immediately after the venting, the air chamber and the power tube are at atmospheric pressure. This is where, in a normal mag, the spring would push the bolt back. In this design, the ram activates and pushes the bolt back to the sear, where the sear holds the bolt back as the on/off is again opened to allow air to flow into the chamber.

    Remember, I'm not using a ram as an "air spring" to replace the bolt spring, but as a "selective spring" where it's only "springy" part of the time. You'll notice that nowhere in the process does the ram actually push against any pressurized air, like the bolt spring does. I know that the bolt spring doesn't hold the bolt back (which presents another question:why not just a really light bolt spring?).

    Overall, this seems to me that it would increase the efficiency of a mag greatly. The air lost to the 3-way is very small in comparison to the amount of air that is required to move against a very tough bolt spring. If there are any flaws in this, please tell me. I am by no means thinking that I am anything special, I'm just a senior in high school.

    Oh, and could you tell me any sources that I could find some of these really small mechanical and electronic 3-ways and the small rams and all? I have a few sources that I got some catalogs from, but I think they're for more like big ole orders of like 10000 or so. Ebay's no good cause I couldn't be able to get consistency in the things if I made more than one frame for myself, and plus they don't have exactly what I would be looking for. Thanks a lot
    Bert

  28. #28
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    bertmcmahan-
    well that's what we're talking about too. the sear still holding the bolt. the bolt ram just pushes the bolt back to reset. we're talkng about the same thing. as far as that part of it is concerned.

    but I think your under the false impression that this would make the mag more efficient. the mag doesn't use 400 to 500 psi operating pressure because the bolt spring is too stiff, it uses it because it needs it to get the ball up to speed.
    I believe it's because of the bolt design, and the basic design of the system. air in the chamber is expanded when the bolt moves forward, losing energy, then it must go around the bolt center piston and through the three ports in the front of the bolt. this coupled with the fact the air is able to leak out around the piston as soon as the seal of the power tube o-ring is broken. I've heard that it is not a significant amount of air, but where does blow-back come from? if you want to make a mag more efficinet, you have to better utilize the air it consumes per shot.

    when a mag fires a ball, the chamber does not go all the way down to atmosheric pressure. it goes down to about 50 or 60 psi. if it went all the way down, it would take up more air and time just to get it back up to usable pressure.

    aut911-
    yeah flow controls are not as accurate as electronic control. it would be a better design to use separate 3-way solenoid valves, just take up more space. I don't know if you could fit that much stuff in the grip. although, it might be possible, if you used the rail as a manifold, putting the bolt ram up tight to the rail. yeah it could probably be done.

    target practice-

    uhm... you mean you don't know anything about solenoids too, not just pneumatics. if you did, you wouldn't have made such a suggestion.
    you should research solenoids a bit. they are not usually interchangeable for processes that use air cylinders.

  29. #29
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    Fascinating thread. I have an idea that might or might not work. If it does work, it would eliminate the need for a three way, or solenoid valve.

    Has anyone seen how an SKS or AK 47 operates? They use a piston that bleeds gas off of the barrel as the bullet is travelling forward once the bullet passes the hole where the barrel is tapped, the pressure increases enough to push the piston backwards, cocking the rifle. If a ram were attached to the bolt and a hole was placed in front of the ball, when the ball passed the hole, some of the pressure used to propel the ball could be redirected to actuate the ram, recocking the bolt. This pressure would be dependant on a good paint to barrel match, and might just be enough to re cock the bolt if there is no pressure behind it. (As in, the trigger has not yet released so there is no pressure in the power tube).
    Obviously, once the ball cleared the first ports in the barrel, air would vent out the ports and the pressure would drop to the point that the ram would not function. Another problem with this design is that in the event the marker fires with no ball in the breech, there would be no back pressure to operate the ram, and the marker would not re-cock.

  30. #30
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    Hmm... Good point about the air having too far to travel. I didn't really think about that one. However, couldn't the efficiency be increased some ? The pressure needed might be slightly lower. Of course, low pressure isn't exactly something thats just great to have. Not any really huge benefits, if any, that I can see. I'll need to think a little more about this one...
    BTW do any of you guys know where I can get some of the really small valves and cylinders for this stuff off the shelf? I don't wanna have a billion of them custom made for me, just like 4 or so that I can play with.

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